Got check engine Light on after diving on a rainy day on the road. Obd reader gives the code P2196.

I have looked around and common issues seems to be the be is; P2196 TOYOTA - Oxygen Air/Fuel Sensor Signal Stuck Rich Bank 1 Sensor 1.

I have searched everywhere to find where the sensor is on the car. Where is bank 1??

I know how to check with multimeter if the sensor is bad but i have first find it to do that :) i believe its connection problems but we will se about that. Does anyone know the location for bank one for my toyota yaris xp9f(a) 2010?

engine exhaust system: you only have a bank 1. if your engine was a V configuration, (V4, V6, V8) you would have bank 1 and bank 2. sensor 1 is before the catalytic converter, (near the engine) sensor 2 is after the catalytic converter.
sensor 1: monitors the engine performance and adjusts fuel injection
sensor 2: monitors catalyst efficenty
i think it sounds like you need to replace sensor. replacement is easy (most of the time)

Hmm tested my Air fuel sensor (o2) and I have restistance. I cleared the fault code and it came on after 1 1/2 day diving. I had this issue earlier and it seems to be more common that the light goes on when its could Outdoor. +3 or lower so im thinking that the sensor is affected by lower temperature or could something else trigger same fault code?

Im asking do to the Light can be cleared and Everything seems ok untill its getting colder outside :)

that makes sense because the engine runs richer at cold start up. if the air filter was really dirty it might throw a rich fault. an incorrect signal from a dirty MAF sensor may cause a rich condition. a leaking injector could cause fault. this is what i would do:
check condition of air filter. if it is dirty, replace. wile at the auto parts store getting filter, pick up some MAF cleaner. (Mass Air Flow) the MAF is the sensor that is in the air box you remove to change air filter. remove the 2 bolts and pull sensor up. clean with MAF cleaner. allow a few minutes for cleaner to evaporate before reinstalling. i would also replace the A/F sensor. it sounds like it might be lazy. they do wear out. don't buy from the dealership, too expensive. BUT, only buy Denso, (234-9052) Toyota,(89467-52020) or NTK (24661) brands.

that makes sense because the engine runs richer at cold start up. if the air filter was really dirty it might throw a rich fault. an incorrect signal from a dirty MAF sensor may cause a rich condition. a leaking injector could cause fault. this is what i would do:
check condition of air filter. if it is dirty, replace. wile at the auto parts store getting filter, pick up some MAF cleaner. (Mass Air Flow) the MAF is the sensor that is in the air box you remove to change air filter. remove the 2 bolts and pull sensor up. clean with MAF cleaner. allow a few minutes for cleaner to evaporate before reinstalling. i would also replace the A/F sensor. it sounds like it might be lazy. they do wear out. don't buy from the dealership, too expensive. BUT, only buy Denso, (234-9052) Toyota,(89467-52020) or NTK (24661) brands.

Thanks SirDigiby.
I started with cleaning and clearing the sensor connectors with Electric cleaner and this without successivt. No Light came on my way to work (25 km) but driving home did Light it up after 20 minutes of driving :( i dont get any symptoms more then check engine light. My thoughts has also been on looking into the mass Air flow sensor so i will do that and check the air filter. If still the problems occurs then my last step will be buying a new a/f sensor - toyodiy homepage gives me part number 89467-52070
I will se if i find denso in first hand before looking at other producers :)
Thank you for your advice :) i will be putting in the outcome when im done. Will take a while before reposting :)